A bit late on the N8 impressions but here we go!
The one I purchased was a universal demo unit, so as usual expect variation between what I've experienced and a potentially custom unit that you purchase yourself
The N8 generally strikes me as what might just be the best basshead all-rounder of everything I've tried. It has that typical 64 tia treble extension that the drivers have become famous for, with a very prominent and present midrange, and heavy bass. I can't say that this isn't a basshead IEM, but the bass is fast enough to not call as much attention to itself as the Legend X for example, where the texture and decay are just begging you to listen to them. No BA configuration can pull of the N8's lows, but there are certain common characteristics in that the N8's bass has detail, control and speed typical for a BA, but the slam and decay that only a DD can really perform
My first impulse was to go with my rap and EDM playlists, but I'd actually say the N8 finds a better home in jazz and other more heavily acoustic genres, where the midrange timbre and treble presence can really shine. Honestly as far as the mids are concerned, I think I'd still take it over loads of other things I've owned, including the A18t which sounds a bit thinner in comparison.
As to the treble, it doesn't reach the detail of the A18t, or the Z1R's crazy performance but it gets the extension right. I personally find that the quantity of the highs is slightly excessive though, as it makes all the frequencies feel somewhat boosted, reminiscent of the FiR M5. The midrange still outperforms that of the M5 though, with comparable bass - though it might be slightly more in quantity. All in all I'd pick the N8 over the M5 either way due to its far superior midrange texture.
I reached out to Vitaliy regarding differences I might be expecting if I were to get a custom N8 and he did mention I might be getting slightly less treble on the custom, which would be a welcome improvement on the overall signature of the monitor. Personally though, I doubt I'd be keeping it for too long considering the Z1R tends to outperform the N8 in most aspects, and the added bass quantity in the N8 isn't something I'd absolutely need - though I am enjoying that quite a bit for the time being
As to technicalities, I'd say it's reasonable. It's not the most detailed monitor on the market, but it certainly isn't the worst either. Add to that the amazing texture that it brings to the table and rather good resolution and you actually end up with a pretty great overall package. I'm personally not a fan of the "boost all frequencies" signature, but if it is true that the custom brings down the treble a notch that's that issue resolved.
As to the comparison everyone is wondering about, I'd say I like the N8 better than I like the Legend X - the latter consumes too much detail due to its bass quantity and presence, and the lows generally tend to steal a bit too much attention for my liking. I also find the treble to be way too little there (while the N8 universal does have a bit too much) - maybe something between the two would be best for me. Also considering the price difference and APEX pressure vent I personally couldn't recommend the LX over the N8
Might be posting the demo unit for sale soon, so as usual, if you gots an offer, hit me up!